0

In my project, I have to read the input pin number(send by RPi), where 8 sensors are attached to Arduino Nano, after reading Arduino Nano send the real-time values of all sensors through serial USB communication. All is fine, but my problem is that I need to speed up the sending of data since it takes to long to read from Rasberry pi. I put the delay of 70 milliseconds but if I try to reduce more than that, I encounter a problem i.e data overwrites. My baud rate is 115200. Kindly help me with the code to make it fast.

int analogInputPin;
float voltage;

void setup() {
  // initialize serial communications at 9600 bps:
  Serial.begin(115200);
}

void loop() {
  // if any data on the serial port are available
  // read it and try to update the analogInputPin
  // based on the number that was read on the serial  
  if (Serial.available() > 0) {
    analogInputPin = Serial.parseInt();
  }

  // read the analog value:
  int analogInputPinValue = analogRead(analogInputPin);
  voltage=(5./1023.)*analogInputPinValue;

  // print the results to the serial port:
  // the output should have the following form: INPUTPIN:VALUE
  // followed by a newline character
  Serial.print(analogInputPin);
  Serial.print(":");
  Serial.print(voltage);
  Serial.println("");

  // wait 50 milliseconds before the next loop
  delay(50);
}
1

parseInt reads digits and stops after a non-digit characters occurs or the function times out because no next characters arrives. The timeout is at default 1 second. So this is where you loose time.

Simplest solution for your code is to send some non-digit character after the number sent from Raspberry. This will terminate parseInt immediately. Usual is to send a new line character. It will separate the numbers nice if you debug the communication with prints to serial terminal.

Not a very good option, but I mention it, is to set the timeout of blocking read functions like the parseInt to a smaller time with Serial.setTimeout(ms).

To really speed up the communication you would send the numbers in binary form and not as text like you do now.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.